Jing Yin, Jiahao Li, Ahui Yang and Shunyao Cai
In regarding to operational efficiency and safety improvements, multiple tower crane service scheduling problem is one of the main problems related to tower crane operation but…
Abstract
Purpose
In regarding to operational efficiency and safety improvements, multiple tower crane service scheduling problem is one of the main problems related to tower crane operation but receives limited attention. The current work presents an optimization model for scheduling multiple tower cranes' service with overlapping areas while achieving collision-free between cranes.
Design/methodology/approach
The cooperative coevolutionary genetic algorithm (CCGA) was proposed to solve this model. Considering the possible types of cross-tasks, through effectively allocating overlapping area tasks to each crane and then prioritizing the assigned tasks for each crane, the makespan of tower cranes was minimized and the crane collision avoidance was achieved by only allowing one crane entering the overlapping area at one time. A case study of the mega project Daxing International Airport has been investigated to evaluate the performance of the proposed algorithm.
Findings
The computational results showed that the CCGA algorithm outperforms two compared algorithms in terms of the optimal makespan and the CPU time. Also, the convergence of CCGA was discussed and compared, which was better than that of traditional genetic algorithm (TGA) for small-sized set (50 tasks) and was almost the same as TGA for large-sized sets.
Originality/value
This paper can provide new perspectives on multiple tower crane service sequencing problem. The proposed model and algorithm can be applied directly to enhance the operational efficiency of tower cranes on construction site.
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Xu Li, Jun Li, Xiaoyi Zhang, Jianfeng Gao and Chao Zhang
Viscous dampers are commonly used in large span cable-stayed bridges to mitigate seismic effects and have achieved great success.
Abstract
Purpose
Viscous dampers are commonly used in large span cable-stayed bridges to mitigate seismic effects and have achieved great success.
Design/methodology/approach
However, the nonlinear analysis on damper parameters is usually computational intensive and nonobjective. To address these issues, this paper proposes a simplified method to determine the viscous damper parameters for double-tower cable-stayed bridges. An empirical formula of the equivalent damping ratio of viscous dampers is established through decoupling nonclassical damping structures and linearization of nonlinear viscous dampers. Shaking table tests are conducted to verify the feasibility of the proposed method. Moreover, this simplified method has been proved in long-span cable-stayed bridges.
Findings
The feasibility of this method is verified by the simplified model shaking table test. This simplified method for determining the parameters of viscous dampers is verified in cable-stayed bridges with different spans.
Originality/value
This simplified method has been validated in cable-stayed bridges with various spans.
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Guichen Zhang, Hongtao Zhang, Heng Peng and Yinghua Liu
High-rise tower structures supported by side frame structure and viscous damper in chemical industry can produce plasticity under dynamic loads, such as wind and earthquake, which…
Abstract
Purpose
High-rise tower structures supported by side frame structure and viscous damper in chemical industry can produce plasticity under dynamic loads, such as wind and earthquake, which will heavily influence the long-term safety operation. This paper aims to systematically study the optimization design of these structures by free vibration and dynamic shakedown analysis.
Design/methodology/approach
The transfer matrix method and Euler–Bernoulli beam vibration are used to study the free vibration characteristic of the simplified high-rise tower structure. Then the extended stress compensation method is used to construct the self-equilibrated stress by using the dynamic load vertexes and the lower bound dynamic shakedown analysis for the structure with viscous damper. Using the proposed method, comprehensive parametric studies and optimization are performed to examine the shakedown load of high-rise tower with various supported conditions.
Findings
The numerical results show that the supported frame stiffness, attached damper or spring parameters influence the free vibration and shakedown characters of high-rise tower very much. The dynamic shakedown load is lowered down quickly with external load frequency increasing to the fundamental natural frequency of the structure under spring supported condition, while changed little with the damping connection. The optimized location and parameter of support are obtained under dynamical excitations.
Research limitations/implications
In this study, the high-rise tower structure is simplified as a cantilever beam supported by a short cantilever beam and a damper under repeated dynamic load, and linear elasticity for solid is assumed for free vibration analysis. The current analysis does not account for effects such as large deformation, stochastic external load and nonlinear vibration conditions which will inevitably be encountered and affect the load capacity.
Originality/value
This study provides a comprehensive method for the dynamical optimization of high-rise tower structure by combining free vibration and shakedown analysis.
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The aim of the study is to provide a comprehensive understanding of interrelations of structural systems and main planning considerations in supertall buildings (≥300 m).
Abstract
Purpose
The aim of the study is to provide a comprehensive understanding of interrelations of structural systems and main planning considerations in supertall buildings (≥300 m).
Design/methodology/approach
Data were collected from 140 contemporary supertall towers using the case study method to analyze structural systems in the light of the key design considerations to contribute to the creation of more viable supertall building projects.
Findings
Central core typology, outriggered frame system, composite material and tapered prismatic and free forms were the most preferred features in supertall building design. Shear walled frame and tube systems occurred mostly in the 300–400 m height range, while outriggered frame systems were in the range of 300–600 m in height. Asia, the Middle East and North America mainly preferred outriggered frame systems, followed by tube systems. Considering the building function and form, the most preferred structural system in each of these groups was outriggered frame system, while mixed-use function stood out in all structural systems except in shear walled frame system.
Originality/value
To date, there has been no comprehensive study in the literature of the interrelations of structural systems and important planning considerations in the design of contemporary supertall towers through a large set of study samples. This critical issue was multidimensionally explored in this paper in light of 140 detailed case studies of supertall buildings around the world.
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Smitha Gopinath, Nagesh Iyer, J. Rajasankar and Sandra D'Souza
The purpose of this paper is to present integrated methodologies based on multilevel modelling concepts for finite element analysis (FEA) of reinforced concrete (RC) shell…
Abstract
Purpose
The purpose of this paper is to present integrated methodologies based on multilevel modelling concepts for finite element analysis (FEA) of reinforced concrete (RC) shell structures, with specific reference to account for the nonlinear behaviour of cracked concrete and the other associated features.
Design/methodology/approach
Geometric representation of the shell is enabled through multiple concrete layers. Composite characteristic of concrete is accounted by assigning different material properties to the layers. Steel reinforcement is smeared into selected concrete layers according to its position in the RC shell. The integrated model concurrently accounts for nonlinear effects due to tensile cracking, bond slip and nonlinear stress‐strain relation of concrete in compression. Smeared crack model having crack rotation capability is used to include the influence of tensile cracking of concrete. Propagation and change in direction of crack along thickness of shell with increase in load and deformation are traced using the layered geometry model. Relative movement between reinforcing steel and adjacent concrete is modelled using a compatible bond‐slip model validated earlier by the authors. Nonlinear iterative solution technique with imposed displacement in incremental form is adopted so that structures with local instabilities or strain softening can also be analysed.
Findings
Proposed methodologies are validated by evaluating ultimate strength of two RC shell structures. Nonlinear response of McNeice slab is found to compare well with that of experiment available in literature. Then, a RC cooling tower is analysed for factored wind loads to study its behaviour near ultimate load. Numerical validation demonstrates efficacy and usefullness of the proposed methodologies for nonlinear FEA of RC shell structures.
Originality/value
The present paper integrates critical methodologies used for behaviour modelling of concrete and reinforcement with the physical interaction among them. The study is unique by considering interaction of tensile cracking and bond‐slip which are the main contributors to nonlinearity in the nonlinear response of RC shell structures. Further, industrial application of the proposed modelling strategy is demonstrated by analysing a RC cooling tower shell for its nonlinear response. It is observed that the proposed methodologies in the integrated manner are unique and provide stability in nonlinear analysis of RC shell structures.
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Syed Awais Ali Shah, Bingtuan Gao, Ajeet Kumar Bhatia, Chuande Liu and Arshad Rauf
Barge-type offshore floating wind turbine (OFWT) commonly exhibits an under-actuated phenomenon in an offshore environment, which leads to a potential vibration-damping hazard…
Abstract
Purpose
Barge-type offshore floating wind turbine (OFWT) commonly exhibits an under-actuated phenomenon in an offshore environment, which leads to a potential vibration-damping hazard. This article aims to provide a new robust output feedback anti-vibrational control scheme for the novel translational oscillator with rotational actuator (TORA) based five-degrees of freedom (5-DOF) barge-type OFWT in the presence of unwanted disturbances and modeling uncertainties.
Design/methodology/approach
In this paper, an active control technique called TORA has been used to design a 5-DOF barge-type OFWT model, where the mathematical model of the proposed system is derived by using Euler–Lagrange's equations. The robust hierarchical backstepping integral nonsingular terminal sliding mode control (HBINTSMC) with an adaptive gain is used in conjunction with extended order high gain observer (EHGO) to achieve system stabilization in the presence of unwanted disturbances and modeling uncertainties. The numerical simulations based on MATLAB/SIMULINK have been performed to demonstrate the feasibility and effectiveness of the proposed model and control law.
Findings
The numerical simulation results affirm the accuracy and efficiency of the proposed control law for the TORA based OFWT system. The results demonstrate that the proposed control law is robust against unwanted disturbances and uncertainties. The unknown states are accurately estimated by EHGO which enables the controller to exhibit improved stabilization performance.
Originality/value
A new mathematical model of the 5-DOF barge-type OFWT system based on TORA is the major contribution of this research paper. Furthermore, it provides a new adaptive anti-vibration control scheme by incorporating the EHGO for the proposed model.
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Tariq P. Sattar, Hernando Leon Rodriguez and Bryan Bridge
Structural integrity inspection of offshore wind turbine blades poses problems of gaining access to the blades, danger to human operatives and large costs of removing a blade and…
Abstract
Purpose
Structural integrity inspection of offshore wind turbine blades poses problems of gaining access to the blades, danger to human operatives and large costs of removing a blade and transporting it off‐shore for inspection. The purpose of this paper is to show that a climbing robot that can perform in situ blade inspection with micro/nano focus computed axial X‐ray tomography is a solution to find defects in the thickest blade sections and reduce the cost of inspection.
Design/methodology/approach
The weight of such an inspection system will be high, typically 200 kg and cross sectional scanner dimensions of 1 × 2 m to envelope a blade. The design of a climbing ring robot that completely encircles a turbine tower, typically 3 m in diameter, will provide the best means of climbing with this payload. Because of the development costs of such a huge robot, the optimal design path is to first prototype a small scale model.
Findings
First results on such a model are described and from its performance the load carrying capabilities of a full scale version computed. The robot is able to climb either straight up or down, or with a spiralling motion, or rotate around the circumference at the same height. Furthermore, the design is entirely modular thus enabling easy on‐site assembly of the robot.
Originality/value
A climbing robot with high payload and versatile motion capability, with adhesive forces between the robot and climbing surface provided entirely by mechanical means rather than by vacuum suction or magnetic force, making the system much safer and easier to manipulate.
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Telemedicine is delivered to patient anywhere during emergency treatment care, and medical information is transferred from one site of patient to another site of specialist…
Abstract
Purpose
Telemedicine is delivered to patient anywhere during emergency treatment care, and medical information is transferred from one site of patient to another site of specialist doctors by using mobile internet communication. Some rural areas have slow internet speed because of weak internet signal propagation from mobile towers. A good design of antenna is needed to improve mobile internet speed for big medial data transmission in telemedicine application. Hence, this paper aims to propose economically low-cost design of antenna.
Design/methodology/approach
Telemedicine recommended to design the satellite frequency modulation dish (SAT FMD) antenna ( where in FM radio antenna, dish antenna are combined ) to improve the internet speed at Telemedicine system and Hospitals for purpose of Telemedicine communication and information for emergency treatment.
Findings
In the proposed system, designed SAT FMD satellite-based antenna improved internet speed is achieved at 90.6% accuracy in this research method. Finding latitude and longitude angles to identify the patient location, nearest hospitals location and finding distance, shortest path routing between patient and hospital. Finding elevation, Azimuth, latitude, longitude, skew for alignment dish to focus satellite and mobile cell tower to improve internet speed at telemedicine area and hospitals and reduced transmission delay and nodal delay of big medical data.
Social implications
The social awareness among people can be shared information of accident patient to communicate Hospital and Ambulance driver by internet mobile app tools and help find nearest hospitals to emergency treatment for accident people.
Originality/value
This paper presents SAT FMD antenna model based on satellite dish antenna consisting of FM radio receiver antenna and dish antenna for telemedicine communication.
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David Wadley, Jung Hoon Han and Peter Elliott
Professionals’ market knowledge and business experience can facilitate transactions of residential property potentially impacted by stigmatised installations, such as large-scale…
Abstract
Purpose
Professionals’ market knowledge and business experience can facilitate transactions of residential property potentially impacted by stigmatised installations, such as large-scale public infrastructure. The purpose of this paper is to explore perceptions and assessments among homeowners, valuers (appraisers) and real estate agents (realtors) regarding infrastructure in general and high voltage overhead transmission lines (HVOTLs) in particular.
Design/methodology/approach
Informed by a literature review, separate surveys in Queensland, Australia, analyse via non-parametric and parametric means informational and perceptual variables concerning HVOTLs among 600 homeowners, 90 valuers and 90 real estate agents.
Findings
The findings reveal statistically significant differences in risk and valuation perceptions of homeowners, valuers and real estate agents relating to the placement of major linear forms of infrastructure.
Research limitations/implications
This study adds to a now-solid body of literature pertaining to property effects of HVOTLs. It extends the analysis among classes of real estate professionals and provides new comparisons for further analysis and commentary.
Practical implications
The results speak to property professionals, land use planning and electricity authorities. Prior research can be triangulated with that obtained here from valuers and real estate agents who act as informants, gatekeepers and confidants in the market place. Various hypotheses address specific points of professional practice.
Social implications
This study shows that property professionals’ disposition to HVOTLs and other large-scale infrastructure is likely to be a good deal more measured than that of homeowners, so that valuers and real estate agents might exercise a mediating influence in placement and installations decisions.
Originality/value
This research raises understanding of differences in market knowledge and perception of essential infrastructure among clients and property agents. As a point of difference, it concentrates on examining empirically what texts refer to as “information asymmetry” in residential real estate markets.
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Keywords
Brent Lagesse, Shuoqi Wang, Timothy V. Larson and Amy Ahim Kim
The paper aims to develop a particle matter (PM2.5) prediction model for open-plan office space using a variety of data sources. Monitoring of PM2.5 levels is not widely applied…
Abstract
Purpose
The paper aims to develop a particle matter (PM2.5) prediction model for open-plan office space using a variety of data sources. Monitoring of PM2.5 levels is not widely applied in indoor settings. Many reliable methods of monitoring PM2.5 require either time-consuming or expensive equipment, thus making PM2.5 monitoring impractical for many settings. The goal of this paper is to identify possible low-cost, low-effort data sources that building managers can use in combination with machine learning (ML) models to approximate the performance of much more costly monitoring devices.
Design/methodology/approach
This study identified a variety of data sources, including freely available, public data, data from low-cost sensors and data from expensive, high-quality sensors. This study examined a variety of neural network architectures, including traditional artificial neural networks, generalized recurrent neural networks and long short-term memory neural networks as candidates for the prediction model. The authors trained the selected predictive model using this data and identified data sources that can be cheaply combined to approximate more expensive data sources.
Findings
The paper identified combinations of free data sources such as building damper percentages and weather data and low-cost sensors such as Wi-Fi-based occupancy estimator or a Plantower PMS7003 sensor that perform nearly as well as predictions made based on nephelometer data.
Originality/value
This work demonstrates that by combining low-cost sensors and ML, indoor PM2.5 monitoring can be performed at a drastically reduced cost with minimal error compared to more traditional approaches.